1 files changed, 66 insertions, 25 deletions

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 343083fec258..d52999c43336 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -79,13 +79,23 @@
 /*
  * Global page accounting.  One instance per CPU.  Only unsigned longs are
  * allowed.
+ *
+ * - Fields can be modified with xxx_page_state and xxx_page_state_zone at
+ * any time safely (which protects the instance from modification by
+ * interrupt.
+ * - The __xxx_page_state variants can be used safely when interrupts are
+ * disabled.
+ * - The __xxx_page_state variants can be used if the field is only
+ * modified from process context, or only modified from interrupt context.
+ * In this case, the field should be commented here.
  */
 struct page_state {
         unsigned long nr_dirty;         /* Dirty writeable pages */
         unsigned long nr_writeback;     /* Pages under writeback */
         unsigned long nr_unstable;      /* NFS unstable pages */
         unsigned long nr_page_table_pages;/* Pages used for pagetables */
-        unsigned long nr_mapped;        /* mapped into pagetables */
+        unsigned long nr_mapped;        /* mapped into pagetables.
+                                         * only modified from process context */
         unsigned long nr_slab;          /* In slab */
 #define GET_PAGE_STATE_LAST nr_slab
 
@@ -97,32 +107,40 @@ struct page_state {
         unsigned long pgpgout;          /* Disk writes */
         unsigned long pswpin;           /* swap reads */
         unsigned long pswpout;          /* swap writes */
-        unsigned long pgalloc_high;     /* page allocations */
 
+        unsigned long pgalloc_high;     /* page allocations */
         unsigned long pgalloc_normal;
+        unsigned long pgalloc_dma32;
         unsigned long pgalloc_dma;
+
         unsigned long pgfree;           /* page freeings */
         unsigned long pgactivate;       /* pages moved inactive->active */
         unsigned long pgdeactivate;     /* pages moved active->inactive */
 
         unsigned long pgfault;          /* faults (major+minor) */
         unsigned long pgmajfault;       /* faults (major only) */
+
         unsigned long pgrefill_high;    /* inspected in refill_inactive_zone */
         unsigned long pgrefill_normal;
+        unsigned long pgrefill_dma32;
         unsigned long pgrefill_dma;
 
         unsigned long pgsteal_high;     /* total highmem pages reclaimed */
         unsigned long pgsteal_normal;
+        unsigned long pgsteal_dma32;
         unsigned long pgsteal_dma;
+
         unsigned long pgscan_kswapd_high;/* total highmem pages scanned */
         unsigned long pgscan_kswapd_normal;
-
+        unsigned long pgscan_kswapd_dma32;
         unsigned long pgscan_kswapd_dma;
+
         unsigned long pgscan_direct_high;/* total highmem pages scanned */
         unsigned long pgscan_direct_normal;
+        unsigned long pgscan_direct_dma32;
         unsigned long pgscan_direct_dma;
-        unsigned long pginodesteal;     /* pages reclaimed via inode freeing */
 
+        unsigned long pginodesteal;     /* pages reclaimed via inode freeing */
         unsigned long slabs_scanned;    /* slab objects scanned */
         unsigned long kswapd_steal;     /* pages reclaimed by kswapd */
         unsigned long kswapd_inodesteal;/* reclaimed via kswapd inode freeing */
@@ -136,31 +154,54 @@ struct page_state {
 extern void get_page_state(struct page_state *ret);
 extern void get_page_state_node(struct page_state *ret, int node);
 extern void get_full_page_state(struct page_state *ret);
-extern unsigned long __read_page_state(unsigned long offset);
-extern void __mod_page_state(unsigned long offset, unsigned long delta);
+extern unsigned long read_page_state_offset(unsigned long offset);
+extern void mod_page_state_offset(unsigned long offset, unsigned long delta);
+extern void __mod_page_state_offset(unsigned long offset, unsigned long delta);
 
 #define read_page_state(member) \
-        __read_page_state(offsetof(struct page_state, member))
+        read_page_state_offset(offsetof(struct page_state, member))
 
 #define mod_page_state(member, delta)   \
-        __mod_page_state(offsetof(struct page_state, member), (delta))
-
-#define inc_page_state(member)  mod_page_state(member, 1UL)
-#define dec_page_state(member)  mod_page_state(member, 0UL - 1)
-#define add_page_state(member,delta) mod_page_state(member, (delta))
-#define sub_page_state(member,delta) mod_page_state(member, 0UL - (delta))
-
-#define mod_page_state_zone(zone, member, delta)                                \
-        do {                                                                    \
-                unsigned offset;                                                \
-                if (is_highmem(zone))                                           \
-                        offset = offsetof(struct page_state, member##_high);    \
-                else if (is_normal(zone))                                       \
-                        offset = offsetof(struct page_state, member##_normal);  \
-                else                                                            \
-                        offset = offsetof(struct page_state, member##_dma);     \
-                __mod_page_state(offset, (delta));                              \
-        } while (0)
+        mod_page_state_offset(offsetof(struct page_state, member), (delta))
+
+#define __mod_page_state(member, delta) \
+        __mod_page_state_offset(offsetof(struct page_state, member), (delta))
+
+#define inc_page_state(member)          mod_page_state(member, 1UL)
+#define dec_page_state(member)          mod_page_state(member, 0UL - 1)
+#define add_page_state(member,delta)    mod_page_state(member, (delta))
+#define sub_page_state(member,delta)    mod_page_state(member, 0UL - (delta))
+
+#define __inc_page_state(member)        __mod_page_state(member, 1UL)
+#define __dec_page_state(member)        __mod_page_state(member, 0UL - 1)
+#define __add_page_state(member,delta)  __mod_page_state(member, (delta))
+#define __sub_page_state(member,delta)  __mod_page_state(member, 0UL - (delta))
+
+#define page_state(member) (*__page_state(offsetof(struct page_state, member)))
+
+#define state_zone_offset(zone, member)                                 \
+({                                                                      \
+        unsigned offset;                                                \
+        if (is_highmem(zone))                                           \
+                offset = offsetof(struct page_state, member##_high);    \
+        else if (is_normal(zone))                                       \
+                offset = offsetof(struct page_state, member##_normal);  \
+        else if (is_dma32(zone))                                        \
+                offset = offsetof(struct page_state, member##_dma32);   \
+        else                                                            \
+                offset = offsetof(struct page_state, member##_dma);     \
+        offset;                                                         \
+})
+
+#define __mod_page_state_zone(zone, member, delta)                      \
+ do {                                                                   \
+        __mod_page_state_offset(state_zone_offset(zone, member), (delta)); \
+ } while (0)
+
+#define mod_page_state_zone(zone, member, delta)                        \
+ do {                                                                   \
+        mod_page_state_offset(state_zone_offset(zone, member), (delta)); \
+ } while (0)
 
 /*
  * Manipulation of page state flags